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Discussion Starter #361
The stupidity continues.

I finally got the rebuilt brake booster back and installed it, along with a new hard line from the booster (above the vacuum banjo bolt) to the brake MC. I bled the brakes (for the 13,544th time) and took her for a drive.

DISAPPOINTED!

Same excessive travel on the pedal and a rather wooden feeling to the brakes, almost like the booster wasn't working.

Back in the garage I confirmed that the booster was holding vacuum. Removing the vacuum hose from it resulted in the tell tale "whoosh."

Up on jackstands and once again I bled all four calipers. Virtually no bubbles. I bled the brake MC and also the booster. Out for another test drive...and as the kids say, "same."

On top of the fact that the brakes just don't feel as good with this newly rebuilt booster, I still have brakes that just aren't right. The pedal's not firm, and it pumps up.

There are no leaks anywhere in the system that I can find.

Here's the status on the components.

Brake MC-new (Classic Alfa)
Calipers-fronts rebuilt, rears rebuilt from Alfa Parts in Berkley.
Booster-rebuilt

I have two options; install the booster that was in it before (which was in the car prior to the accident) or install another booster I have that is used and of unknown condition. I could also remove all three and have the shop test them all. When I call them after the disappointing results they told me they tested the booster after they rebuilt it.

Honestly....single circuit brakes....how hard could it be?

-tj in the Cruz Mtns (where brakes are important)
 

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Any chance you have fresh brake pads, but perhaps worn rotors with a lip, so they just aren't seated well to each other?
 

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Discussion Starter #363
New pads, new rotors.

Any chance you have fresh brake pads, but perhaps worn rotors with a lip, so they just aren't seated well to each other?
-tj in the Cruz Mtns
 

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Try this...

A while back I had a similar experience on car (not an Alfa) I’d fitted a new calliper, pads and discs. I couldn’t get a good pedal however much I tried, after fitting a new master cyl the problem still remained. I must have gone through litres of brake fluid bleeding the system, each time no bubbles exiting the system but a poor pedal. Eventually I tried bleeding each caliper off it’s mount so I could moved it around slightly in case of any trapped air...success! This method got more air from each caliper and resulted in a good feel pedal. With each caliper off you need to place something between the pads to stop them pumping out too far.
I’m sure you don’t want to bleed the system AGAIN, but might be worth a try.
 

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TJ,
Pardon the long post, but I can feel your frustration from way over here...

See post 354: italcaroz suggested bleeding with engine running. He suggests it ensures the booster is pushing fluid too. Not heard that, but is logical and might help if there’s an air pocket there. Did you try it?

See Post 360: Psk hinted at this...take another drive and do plenty of tap-dancing on the pedal. This can help any trapped air migrate upwards to the reservoir.

Your post 361: “Virtually no bubbles” is not “none”. It doesn’t take much air for the pedal to remain soft. Pardon my questioning your bleeding technique, but you do bleed in sequence from farthest calliper to closest, close the bleeder before the pedal is released, close it mid-push on the final close, and NEVER let the reservoir run dry?

Questions:
- After the pedal is quickly pumped, your brakes should still work pretty much as well as they are going to, albeit with a smidge more travel still. Is this what happens, or do they remain poor/unresponsive even with a ‘firmer’ pedal? Are the new pads ‘performance’ items which don’t bite until hot...feeling totally unresponsive when cold?

- If your booster is “bad” (leaking fluid into the vacuum chamber) it should manifest in the engine drawing in and burning brake fluid, which should be easy to see as wetness in the vacuum hose and/or white smoke out the exhaust. Anything to report there?

Lastly, I reckon you’ve bought enough bits...Rather than spending more money replacing parts, consider first asking the brake shop to bleed them for you....and be there, if they’ll let you, to test their thoroughness. Having said that, I do like the look of those speed-bleeders in Post 355.

Good luck.
 

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Discussion Starter #366
TJ,
Pardon the long post, but I can feel your frustration from way over here...

Ranz, no need to apologize. Thank you for taking the time.


See post 354: italcaroz suggested bleeding with engine running. He suggests it ensures the booster is pushing fluid too. Not heard that, but is logical and might help if there’s an air pocket there. Did you try it?

I haven’t tried it but at this point I will. Theoretically it should not matter because the pressure of the brake pedal actually should be enough to push fluid out, but I’ll try it.



See Post 360: Psk hinted at this...take another drive and do plenty of tap-dancing on the pedal. This can help any trapped air migrate upwards to the reservoir.

Oh I’ve driven the ___k out of her....braked hard, pumped the pedal like a bass drum, threshold braked HARD. I live in the mountains with a racetrack for a road, so there’s plenty of places to exercise the brakes. I’m also not sure about bubbles being able to go back up toward the reservoir as I believe there is a check valve in the MC which is meant to prevent it from sucking fluid backward.



Your post 361: “Virtually no bubbles” is not “none”. It doesn’t take much air for the pedal to remain soft. Pardon my questioning your bleeding technique, but you do bleed in sequence from farthest calliper to closest, close the bleeder before the pedal is released, close it mid-push on the final close, and NEVER let the reservoir run dry?

Well when I say “virtually none” is because when you crack the bleed screw a very small amount makes its way past the threads. Those that do are very small, and few and far between. And yes, I start at the right rear, then the left rear, then the right front, and finally the left front. I always keep the brake fluid level in the reservoir above the bottom spigot. I have also bled them with the “pump it three times and hold it” then crack the bleed screw until the pedal bottoms, tighten the bleed screw and then have my assistant (my long suffering wife) let the brake pedal up. I’ve also just cracked the bleed screw and have her slowly push the pedal to the floor only letting her lift after I’ve tightened the bleed screw.



Questions:
- After the pedal is quickly pumped, your brakes should still work pretty much as well as they are going to, albeit with a smidge more travel still. Is this what happens, or do they remain poor/unresponsive even with a ‘firmer’ pedal? Are the new pads ‘performance’ items which don’t bite until hot...feeling totally unresponsive when cold?

The pedal does pump up, the pads are not performance pads.


- If your booster is “bad” (leaking fluid into the vacuum chamber) it should manifest in the engine drawing in and burning brake fluid, which should be easy to see as wetness in the vacuum hose and/or white smoke out the exhaust. Anything to report there?

No wetness around booster, no visible leaks, no smoke in exhaust, hydraulic fluid level remains constant.


Lastly, I reckon you’ve bought enough bits...Rather than spending more money replacing parts, consider first asking the brake shop to bleed them for you....and be there, if they’ll let you, to test their thoroughness. Having said that, I do like the look of those speed-bleeders in Post 355.

I’m not sure that the brake rebuild shop would that work....pretty sure they won’t. One final option is to pressure bleed them from the reservoir, forcing fluid through without using the pedal. I haven’t tried that, and need to fabricate an appropriate brake fluid reservoir top, but that might help.



Good luck.
Thanks again,
-tj
 

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Discussion Starter #367
Thank you!

Does your car have flexible (rubber or stainless braided) lines to the calipers? I’ll try this if I can, but I’m not sure how it will work with hard lines to the caliper.

-tj

A while back I had a similar experience on car (not an Alfa) I’d fitted a new calliper, pads and discs. I couldn’t get a good pedal however much I tried, after fitting a new master cyl the problem still remained. I must have gone through litres of brake fluid bleeding the system, each time no bubbles exiting the system but a poor pedal. Eventually I tried bleeding each caliper off it’s mount so I could moved it around slightly in case of any trapped air...success! This method got more air from each caliper and resulted in a good feel pedal. With each caliper off you need to place something between the pads to stop them pumping out too far.
I’m sure you don’t want to bleed the system AGAIN, but might be worth a try.
 

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Ranz has great feedback n all good areas to consider. The part that jumps out to me is getting some air in bleed. Are you pumping the brakes to bleed or using a vacumn bleeder? My 63 was virtually impossible to bleed the rear drums, so I got a hand pump pressure bleeder n swear by it. It eliminates fluid being frothed, allows a full line bleed at the caliper and is simple n fast to work with. Not sure which calipers you’re running, but if it’s possible to trap air in there, tapping on them may release it. Motorcycle way. Lastly Flexible ss lines might be a worthy sacrifice to the gods of originality for safety’s sake.
 

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These systems are not normally, in my experience, that hard to bleed. So you've confirmed the vacuum side of the booster is good, but that doesn't say anything about how the hydraulic cylinder was rebuilt or whether the air valve is working right. These are pretty simple boosters, I'd be tempted to pull apart and make sure all is OK, but that also requires you have a diagram or other booster to compare to.

In my experience SS hoses feel no different in road use. I wouldn't think new rubber hoses would lead to a soft pedal.

Was the MC rebuilt? Sorry if I haven't read all the way back. You have the right MC diameter to go with the booster? There is also one to go with the early Duetto, no booster.

Andrew
 

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Discussion Starter #371
Peter,

I've tried a number of approaches to bleeding, but the two person method of having someone either depress the brake pedal slowly and firmly after I've cracked the bleed screw, and not lift up on the brake pedal until I've closed the bleed screw, OR, having the person press and release the brake pedal several times before I crack the bleed screw and again, not have them lift until the pedal has gone to the floor and I've closed it have been the most frequently used. I've also used my vacuum bleeder but it's impossible to determine if the system is free of air because the vacuum bleeders suck air through the threads when you crack the bleed screw.

Now, a pressure bleeder is something I've not yet tried, and it's the one I was just thinking about using. I have a pressure tank but I'll need to modify a brake fluid reservoir cap for it as the one on the tool is for a modern car. I know that's how Tom bleeds his brakes.

I'm running larger, later (ATE) calipers front and rear, not by choice, they were on the car when I got it. The only reason I brought up the lack of stainless (or rubber) lines was to address the suggestion that I remove the calipers to bleed them. I don't see how it's possible to remove the caliper with the original hard lines, unless the lines are removed, which of course defeats the purpose.

-tj


Ranz has great feedback n all good areas to consider. The part that jumps out to me is getting some air in bleed. Are you pumping the brakes to bleed or using a vacumn bleeder? My 63 was virtually impossible to bleed the rear drums, so I got a hand pump pressure bleeder n swear by it. It eliminates fluid being frothed, allows a full line bleed at the caliper and is simple n fast to work with. Not sure which calipers you’re running, but if it’s possible to trap air in there, tapping on them may release it. Motorcycle way. Lastly Flexible ss lines might be a worthy sacrifice to the gods of originality for safety’s sake.
 

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Discussion Starter #372
Andrew,

Agreed...it should not be this **** hard. You're right that I did not address the hydraulic component of the booster, although the shop said they tested it. I don't know what comes in the "rebuild kit" for these components, but the shop (Power Brake Exchange) claims that they tested the unit. It also seems curious that I'd have two different brake boosters that exhibited the same behavior. I have one other booster of unknown condition that I could try as well, but I'm not yet there because the one in the car now is supposed to be good.

I only brought up the flexible hoses to address the suggestion of removing the calipers to bleed them in a different position; it's not possible unless you have flexible lines installed, which I don't, and which I don't want. My brake lines are either original soft steel or new copper. The ones at the calipers are the original Alfa hard lines.

Brand new Master Cylinder....the 5th (yes, really, the 5th) one I've installed.

-tj



These systems are not normally, in my experience, that hard to bleed. So you've confirmed the vacuum side of the booster is good, but that doesn't say anything about how the hydraulic cylinder was rebuilt or whether the air valve is working right. These are pretty simple boosters, I'd be tempted to pull apart and make sure all is OK, but that also requires you have a diagram or other booster to compare to.

In my experience SS hoses feel no different in road use. I wouldn't think new rubber hoses would lead to a soft pedal.

Was the MC rebuilt? Sorry if I haven't read all the way back. You have the right MC diameter to go with the booster? There is also one to go with the early Duetto, no booster.

Andrew
 

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I use the top-down pump method, sometimes with a helper, sometimes with a one-way check valve on the bleeder hose, and don't really have issues. I quit using pressure bleeders because they always seem to make a mess at the reservoir.

Bottom-up pressure bleeders can be good; a tank that is pressurized, the fluid comes out a small hose and goes into the bleeder. You have someone at the top, watching for fluid at the reservoir. Do from each corner, you're done. Has the benefit of fluid pushing the air up, which it wants to do anyway.

Andrew
 

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Discussion Starter #374
I tried the bottom up method after Tom suggested it. We could not get any fluid in to the system and wondered if there is a check valve in the MC or booster that prevented it. It's also really hard to keep it from pissing out of the bleed screw (I packed clay in around the bleed screw, which didn't really work.

-tj

I use the top-down pump method, sometimes with a helper, sometimes with a one-way check valve on the bleeder hose, and don't really have issues. I quit using pressure bleeders because they always seem to make a mess at the reservoir.

Bottom-up pressure bleeders can be good; a tank that is pressurized, the fluid comes out a small hose and goes into the bleeder. You have someone at the top, watching for fluid at the reservoir. Do from each corner, you're done. Has the benefit of fluid pushing the air up, which it wants to do anyway.

Andrew
 

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I got a bad MC of this type from Classic Alfa; there was a batch of them. It worked fine but leaked a bit at the pressed-in ball at the top. Had to change it.
Sometimes you get all the air out, then let the system sit overnight and the pedal gets better and better. This was true for me on two cars recently. You let it sit a day or two, doesn't improve?
Andrew
 

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Discussion Starter #376
Andrew,

This has been going on for a year. Every single component in the system, with the exception of a few hard lines and the two junctions has been replaced, sometimes multiple times. I've bled the brake system at least 20 times with various components, and multiple times with each "configuration."

The behavior is the EXACT same behavior that I had with a MC from Alfa Parts, with the MC rebuilt twice by Power Brake Exchange, and with a NOS part I got from Tom. It also exists across two different boosters, one rebuilt and the one that was in the car before the accident. I've bled them, driven it, let it sit over night, driven it again, bled it again, and so on....

I got a bad MC of this type from Classic Alfa; there was a batch of them. It worked fine but leaked a bit at the pressed-in ball at the top. Had to change it.
Sometimes you get all the air out, then let the system sit overnight and the pedal gets better and better. This was true for me on two cars recently. You let it sit a day or two, doesn't improve?
Andrew
-tj
 

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I had a similar issue with a non Alfa car. A guy that was helping me work on the car noticed that one of the calipers was leaking said he'd remove it and rebuild it. After that I had problems like you. Thinking it couldn't be the caliper that was just rebuilt it was suggested to replace the master cylinder which I did and it didn't improve anything. Then I removed the caliper and sent it out to someone else to be rebuilt again and still had the same problem. Then a mechanic friend came and looked at it first isolating that one caliper by clamping closed the hose, we bleed the system and we had good brakes so we knew it had to be the caliper. He said he would rebuild it and when he did he noticed it was filled with grease used to push out the pistons but never fully cleaned out by neither the first guy nor the second guy who rebuilt it. After properly cleaning it out it was reinstalled, the brakes bleed, and everything was fine. Of course mine was easier being I was dealing with only one caliper however this may be something worth looking into.

Joe
 

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It is time, I humbly think, to stop rebuilding and replacing things, this reads like a bleeding issue. These cars are notoriously hard to bleed. I was told you need to jack the rear of the car up as high as physically possible to bleed the rear ...

The suggestion to remove the calipers and bleed while moving them around seems like a good suggestion, otherwise do you have access to a pressure bleeder? OR do you have access to Alfa 105 series specialist ... might be worth the $'s to move forward.


BUT are you sure your MC is adjusted correctly and therefore getting the correct stroke, and opening the ports when it is supposed to. You will never bleed a system if this is not set properly.
Pete
 

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Discussion Starter #379
Thanks for the input. The only components which have remained on the car throughout are the front calipers. They were rebuilt by the same shop that rebuilt the rears, the brake MC, and the booster. So if it's the front calipers, then virtually every component that shop "rebuilt" has been built incorrectly. I'm not saying it's not possible, but it seems improbable.

-tj

I had a similar issue with a non Alfa car. A guy that was helping me work on the car noticed that one of the calipers was leaking said he'd remove it and rebuild it. After that I had problems like you. Thinking it couldn't be the caliper that was just rebuilt it was suggested to replace the master cylinder which I did and it didn't improve anything. Then I removed the caliper and sent it out to someone else to be rebuilt again and still had the same problem. Then a mechanic friend came and looked at it first isolating that one caliper by clamping closed the hose, we bleed the system and we had good brakes so we knew it had to be the caliper. He said he would rebuild it and when he did he noticed it was filled with grease used to push out the pistons but never fully cleaned out by neither the first guy nor the second guy who rebuilt it. After properly cleaning it out it was reinstalled, the brakes bleed, and everything was fine. Of course mine was easier being I was dealing with only one caliper however this may be something worth looking into.

Joe
 

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Discussion Starter #380 (Edited)
PSk,

I have not heard it said that they're hard to bleed. I don't know why that would be the case. They are very simple, single circuit systems. It also doesn't make sense that you would have to jack the car up that high to bleed the rears, the bleeder screws are at the top of the calipers.

Removing the calipers to bleed them is not an option-the lines which connect to the calipers are rigid and the calipers cannot be removed with them in place.

The brake MC has no pre-load on it. In the brake pedal's resting position the piston has no pressure on it.

I have one of the country's most respected 105 wrenches in my backyard. He has helped me with this issue, even driven the car, even helped my bleed the system. He's as puzzled as am I.

-tj in the Cruz Mtns

It is time, I humbly think, to stop rebuilding and replacing things, this reads like a bleeding issue. These cars are notoriously hard to bleed. I was told you need to jack the rear of the car up as high as physically possible to bleed the rear ...

The suggestion to remove the calipers and bleed while moving them around seems like a good suggestion, otherwise do you have access to a pressure bleeder? OR do you have access to Alfa 105 series specialist ... might be worth the $'s to move forward.


BUT are you sure your MC is adjusted correctly and therefore getting the correct stroke, and opening the ports when it is supposed to. You will never bleed a system if this is not set properly.
Pete
 
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